The AI gets "stuck" in the exterior spawn areas on Nighthaven Labs during Training Grounds - Protect Hostage missions. Anywhere from 3-6 terrorists at a time will remain in the spawn areas and not enter the building. This occurs with a high degree of consistency on at least one round during a 4-5 round match. It prevents successful completion of the mission, requiring a remake. It is more likely to occur when selecting replay after a match has concluded as opposed to exiting to the main menu and remaking the match.
The two spawn locations affected are Park and Generator, with the AI getting stuck in the northwest corner of Park and the northeast corner of Generator. The bug occurs most often when defending sites 1F Lounge and 1F Control Room.